Fire-extinguishing system



Patented Aug., l0, 1926.

narran srarss VSAGNMENTS,

B HODE ISLAND, A CORPORATION OF DELAWARE.

FREnE-XTNGUISHING SYSTEM.

Application filed April 3, 1922. Serial No.. 549,007.

rllhis invention relates to improvements in lire extinguishing systems. `More particularly it relates to arrangements tor supply'ing water to a sprinkler system in which two tanks are provided, one an open tank raised above the building in order te supply water by gravity, and the other a tank in which the water is under air pressure. Ordinarily bothv tanks are on the root ot the building, and they discharge into a common pipe which leads downward to the basement whence a riser, equipped it desired, with a d-ry pipe valve, goes up through the various floors to the top and connects with distributing pipes at each floor. In such ay system it is vcustomary to provide a check valve in the yconnection from the gravity tank to the down discharge pipe so that air and water can be maintained at a high pressure in the. air pressure tank. This latterv tank is normally open to the said down pipe but can be cut ott therefrom by a second check valve provided in the connection between the two,

which serves to prevent vtlow ot water from the gravity tank into the pressure tank when the former is discharging into the system. Uponthe opening ot' a sprinkler i-n the distribution system the airv .pressure diminishes with the flow ot water from the air tank, but it has been found in some cases that when the water has been entirely eX- hauste'd therefrom the air following it remains ot sutlicient pressure to keep the check valve closed in the discharge connection from the gravity tank. There is especial danger ot this occurring when the sprinkler which opens is on the top 'floor ot the building so that the head of the gravity tank above the sprinkler is relatively low. In such cases the expected supply of water to the sprinkler system trom the gravity tank tails. It is an objectot the invention to Vprovide tor the prevention of the occurrence ot such an air trap by automatically releasing the Vair from the air pressure tank when the pressure therein has fallen t'o a vpredetermined minimum which can be iigured according to the initial prsesure and the known volume ot water to lbe evacuated thereby. The danger ot failures described above has been so great that whereas a pressure ot y or 90 lbs. to the square inch was standard practice for air and is desirable, insurance companies now are accustomed to prohibit pressure above 60 lbs., which involves a definite lowering ot standards of eiiiciency. By the present invention the normal pressure Vmay Ibe maintained at the former standard, or as much higher as may be desired, ywithout failure et the supplementary supply from the gravity tank in case the water becomes exhausted tronithe a-ir pressure tank.

This improvement is accomplished by providing Yan air escape valve and by associating it with a diaphragm, open to pressure ot 'the air in the tank, that normally tholds the said escape valve closed. The diaphragm is opposed by the pressure of the tank air upon the relatively small area ot the -escape valve, as itV tries to Yesca-pe therethrough,- plus the .pressure of a spring. TWhen the air press-ure is high, the greater area ot the diaphragm causesl the seating pressure to overcome the openi-ng pressure on the valve. As the air pressure diminishes, the ratio between the valve closing pressure acting through the diaphragm and the valve opening pressure ot lair acting on the escape valve remains unchanged, but in magnitude the ditlerence between these pressures gradually ldiminishes until there comes a time when it is less than the pressure by which the said spring supplements the opening pressure of air on the valve; whereupon the escape valve opens and air flows from the tank and thus reduces the ,pressure therein, and in the system, to such a low amount that it is less than the head ot water in the gravity tank above the check valve in its discharge pipe, whereupon this check can no longer bar discharge from the gravity tank. Upon the opening `ot this valve the check valve in the connection to rthe air pressure tank closes, so thatthe supply trom the gravity tank is thereafter wholly discharged into the sprinkler system.

In the accompanying drawings Figure .1 is van elevation partly in section of a building equipped with a sprinkler system embodying the invention;

Figure 2 is an enlarged view partly in section, vshowing the pressure release valve ot the system.

Figure 3 is a section on line 3-3 ot Fig- 'ure 2.

Referring to the drawings a building',

with doors shown in cross section, is protected by a sprinkler system whose water supply is maintained on the roof 12 in two tanks, one a gravity feed tank 14 mounted upon a tower 16, and the other an air pressure tank 18 in a housingl 20. The separate discharge pipes 22 and 24 from these tanks connect with a downward extending pipe 26 leading to the basement, from which a riser 30 extends upward, through the building, to distributing pipes 32 underneath each ceiling', leading to the individual sprinklers 34. In the discharge pipe 22 from the gravity feed tank, above its connection with the pipe 26, there is a check valve 36 adapted to prevent water trom rising into the tank when the pressure on the lower side ot this check valve is greater than that above it. rihis is the normal condition of the system.. when it is charged and awaiting the release ot a sprinkler head, and produced by pumping water into the two tanks, and allowing the system to ll up to a level indicated by the dotted line 88, whereupon the supply of water to the pressure tank is cut The gravity tank is, however, completely filled, its water being prevented from flowing into the air pressure tank, by a check valve 28, located in the connection from the latter tank to the down discharge pipe 26, and closing when the pressure on the lower side is greater than that above it, as when the gravity tank is being filled. While this is taking` place air may be pumped into the pressure tank above the level ot the water therein, as through pipe 37, until the pre-determined pressure is reached, it being evident that as the air pressure builds up and exceeds that ot' the leg of water on the tower tank side the valve 28 will be opened and the valve 36 be closed. This normal static condition continues until the system begins to operate, that is upon the opening of one or more sprinkler heads.

The first discharge of water is to be from the pressure tank 18, and the check valve 36 is to be maintained closed until nearly all ot this air tank water is exhausted, at which time the pressure in the air tank must have been reduced so that the check valve 36 is opened by the head and supply in the lower tank, to add its quota. It has been found in practice, however, that the check valve does not always open. This is due primarily to the head ot the gravity tank above the open sprinkler beinginsufficient to overcome the pressure remaining in the tank 18 after its water has been discharged. To obviate this undesirable and dangerous situation, the present invention provides an automatic release valve for the air pressure tank which will open automatically when the pressure has been reduced to a certain point, sure to be reached before the water in that tank is fully exhausted, or at any rate before the outtlow of air will have been stopped by the balancing water column, assuming the highest sprinkler, to be the one opened. Such a valve indicated in Figure 1 by numeral 40, has two separate connections 42 and 44 with the top ot the air tank above the water line 38, and a vent 46 opening to the atinosphere. The details of construction of one form of this valve are illustrated in Figure 2.

The valve comprises a two part casing 48 and 50 having annular flanges 48 and 50', adapted to register together and to secure between them a diaphragm 52, which constitutes a flexible partition dividing the interior of the casing into separate chambers, 54 and 56, The lower chamber 54 is directly connected to the tank 18 through the nipple 42 thereby exposing one side of the diaahragm to tank pressure. The upper cham ber 56 is part of an escape passage from the tank to the atmosphere, being connected to the tank by pipe 44 and to the atmosphere by pipe 46. The flew ot' air through this passage is controlled by a. valve 58 interposed in the upper chamber 56 and adapted to, maintain the passage closed when a relatively high pressure exists in the tank 18, and to maintain the passage open, when this pressure is reduced to a predetermined point. This valve 58 seats upon a hollow plug 60 supported crosswise the chamber, through the hollow ot which, a portion 62 or" the valve stem projects upward from the valve to be engaged by a spring 64 which in turn extends further upward to seat against an adjustment plug 66 in the upper end o the casing 50. The portion 68 oit the valve stein which projects downward from the valve, is connected by suitable means with the diaphragm 52. The sides ot the upper portion 62 of the stem, where it passes through the opening in the plug seat 60 are Hattened to provide passages by it, so that it is only necessary to move the valve from its seat a relatively small amount, as illustrated in Fig uren, to open the escape passage and thus vent the tank 18, for it is obvious that when the valve is opened, the pressure in the tank 18 can escape therefrom through the pipe connection 44, valve chamber 56 and pipe lilhen the tank is being` charged with air this escape can be entirely cut ott by merely closing the gate valve 70 in the pipe 44, thereby saving` all pressure in the tank from the movement it starts to build up. then the total pressure on the'under side of the diaphragm exceeds that on its upper side including the torce ot the coiled spring the diaphragm will tlex to close the release valve 58. The torce of the spring can be regulated by movement of the screw plug 66, which can be turned in or out upon removal of the closure cap 72, and loosening of the binding nut 74. The adjustment of this termined degree when the gate valve y7() is Vthe pressure in Vthe tank 18 both sides of the valve 58 that is, upon the under side of the diaphragm 52 and upon lthe upper end ofthe valve stem portion 62. The effect of the tank pressure alone `would always keep the valve 58 closed, since the area of the diaphragm is so much greater than the area of the valve, that the total pressure on the latter, even though aided by the atmospheric pressure on the upper side of diaphragm and the weight of the moving parts is always less than the pressure on the diaphragm from below. Accordingly the spring pressure is adjusted to augment the air pressure on the valve stem so that as the latter is reduced in the tank 18 the spring pressure, being constant, will finally overbalance the diminishing difference of the air pressures and will cause the valve 58 to open. This immediately vents the pressure tank to the atmosphere, and allows whatev-er excess pressure then exists in the tank to escape as heretofore described.

rllhe creation of an air trap, due to the complete withdrawal of the water from the pressure tank before the check valve 86 opens, is prevented by the release valve 40, which can be set to operate at any predeof press-ure sure to be reached in the pressure tank before its water is entirely gone. Upon the opening of this valve, and the consequent reduction of the pressure in the tank to that of atmosphere, the head of water in the gravity tank will force the check valve 36 open and close the check valve 28, thus allowing the gravity tank to discharge. This condition will continue until the head on the tower tank side of the check valve is equal to whatever head of water remained in the pressure tank upon the closing of the valve 28, whereupon this valve will open again, and thereafter both check valves will l'remain open until the total supply of water is discharged from both tanks.

I claim as my invention:

l. The combination with a sprinkler system having a gravit-y supply tank and a pressure supply tank arranged to discharge into the system upon the opening of a sprinkler head, of means adapted to withhold discharge from the gravity supply tank until the pressure in the other tank has been reduced to a predetermined degree, and means associated with said pressure tank, operative upon the lowering of its pressure to a. degree higher than said predetermined degree, for automatically reducing the remaining pressure in said tank to the predespring is made opened so that is acting upon termined degree.

2, The combination with a sprinkler systeni having a gravity feed tank and an air pressure feed tank arranged to discharge into a common feed pipe, of a check valve in the connection from the gravity vtank adapted to hold back its water while the pressure of discharge frein the pressure tank is greater than the pressure .of the Vsupply in :the gravity tank; and an escape valve associated `with 'the pressure tank and opera-tive to release the air upon the reduction lof the pressure therein to a predetermined degree, whereby the pressure `of the discharge from the pressure tank becomes less than the pressure of the supply in the gravity tank.

8. A device adapted to be connected with theair space of a pressure tank of a sprinu kier system, comprising a venting valve, means whereby it is maintained closed by relatively high pressure in said tank, and means whereby it is adapted to open upon the reduction `of said high pressure to a predetermined degree, thereby venting said tank. Y

4i. A releasing device for `an air pressure supply tank, comprising a valve casing hav- Y ing a chamber connected continuously with thesaid tank, and having another chamber provided with a. continuously open vent to the atmosphere land with a connection to said tank; a valve subjected to tank lpressure in the iii-st mentioned chamber and to opposite pressure of smaller total value in the other chamber whereby the valve tends to remain closed when the air pressure in the tank is above a predetermined degree; and a spring adapted to supplement said smaller pressure and to open said valve when the air pressure in the Atank falls below said predetermined degree, thereby venting said pressure tank to the atmosphere.

5. A releasing device for an air pressure supply tank, comprising a valve casing having a chamber connected continuously with the said tank, and having another chamber provided with a continuously open vent to the atmosphere and with a connection to said tank; a valve subjected to tank pressure in the first mentioned chamber and to opposite pressure of smaller total value in the other chamber whereby the valve tends to remain closed when the air pressure in the tank is above a predetermined degree; and a spring adapted to supplement saidsmaller pressure and to open said valve when the air pressure in the tank falls below said predetermined degree, thereby venting said pressure tank to the atmosphere; there being means for varying said spring pressure thereby to operate the valve at different predetermined degrees.

6. A releasing device fortan air pressure supply tank, comprising a valve casing having two chambers with separate connections with the tank, and one of them having a vent to the atmosphere; a diaphragm constituting a partition between the chambers,

llO

exposed on one side to the tank pressure and on the other to the vent; a valve in the connection from the tank to the vented chamber With its operating stem secured to the diaphragm, and means, associated With said stem, opposing the tank pressure on the diaphragm, and adapted to open the valve when the said pressure on the diaphragm is reduced, thereby venting the tank to the atmosphere.

7. A releasing device for an air pressure supply tank, comprising a valve chamber having a flexible wall exposed to tank pressure, and having a connection to the tank and a vent to the atmosphere; a valve in said chamber betvveen said connection and said vent, adapted to be closed by tank pressure on said flexible Wall; and spring means operative upon said valve in opposition to said tank pressure to open said valve when the tank pressure falls belovv a predetermined degree, thereby venting the tank to the atmosphere.

8. A releasing device for an air pressure supply tank comprising a valve chamber having a connection with said tank and a vent to the atmosphere; a valve in said chamber between said connection and said vent, having a valve stem projecting trom its opposite sides one end of which has an area exposed to the tank pressure, which area is greater than the area which on the other side of the valve is exposed to the tank pressure through said connection, whereby the resultant pressure tends to maintain the valve closed; and spring means arranged to act on the valve in conjunction With theair pressure on the lesser area, whereby upon the tank pressure being so reduced that the resultant air pressure on the valve stem is less than the spring pressure, he said valve will open and vent the. tank to the atmosphere.

9.V An escape valve for a container whose contents are under pressure comprising a valve adapted to vent said container and arranged to be hele closed normally by pressure of contents therein when such pressure eX- ceeds predetermined limit; combined with means arranged constantly tending to open the valve and adapted te de so When the pres sare Within the container falls belen said predetermined limit.

10. in a lire extinguisher, the combination with a supply nain, a tank for containing water and air under pressure, and a gravity supply tank, both connected With the supply main, of cheek valves for preventing back- -Ward flow towards the tanks, the pressure tank having a vent, a valve for closing said rent, and means to open said valve to vent the pressure tank upon the attainment ot a predetermined condition, in the pressure tank.

Signed at Providence, Rhode Island, this thirtieth day of March, 1922.

JONATHAN C. MELOON. 

